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SubjectRe: [RFT PATCH 2/2] Revert "usb: dwc2: Fix probe problem on bcm2835"
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> On 19.03.2016, at 03:17, Eric Anholt <eric@anholt.net> wrote:
>
> Stefan Wahren <stefan.wahren@i2se.com> writes:
>
>> Hi Eric,
>> hi Martin,
>>
>>> John Youn <John.Youn@synopsys.com> hat am 16. März 2016 um 19:28 geschrieben:
>>>
>>>
>>> On 3/10/2016 11:14 AM, John Youn wrote:
>>>> On 3/9/2016 11:06 AM, Doug Anderson wrote:
>>>>>
>>>>> John: it's pretty clear that there's something taking almost exactly
>>>>> 10ms on my system and almost exactly 50ms on Stefan's system. Is
>>>>> there some register we could poll to see when this process is done?
>>>>> ...or can we look at the dwc2 revision number / feature register and
>>>>> detect how long to delay?
>>>>>

Maybe this difference is related to overclocking settings in the firmware?

>>>
>>> 1. What is the AHB Clock frequency? Is the AHB Clock gated during
>>> Reset?
>
> Low confidence here as I'm tracing lines across a ton of modules, but it
> looks like it comes from the USB AXI clock in peri_image, which is a
> gate on the normal 250Mhz APB clock, but nothing should be touching that
> gate register as part of USB reset as far as I know.
>
Isn’t it possible that this clock (probably BCM2835_CLOCK_VPU) is
changed by the firmware due to overclocking settings in /boot/config.txt?

Martin


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